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    <title>ShellCheck: SC2254 – Quote expansions in case patterns to match literally rather than as a glob.</title>
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    <h1>SC2254 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2254">See this page on GitHub</a>
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    <h2
id="quote-expansions-in-case-patterns-to-match-literally-rather-than-as-a-glob">Quote
expansions in case patterns to match literally rather than as a
glob.</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2254.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="cf">case</span> <span class="va">$input</span> <span class="kw">in</span></span>
<span id="cb1-2"><a href="SC2254.html#cb1-2" aria-hidden="true" tabindex="-1"></a>  <span class="ss">-</span>       <span class="kw">)</span> <span class="bu">echo</span> <span class="st">&quot;Reading from stdin...&quot;</span> <span class="cf">;;</span></span>
<span id="cb1-3"><a href="SC2254.html#cb1-3" aria-hidden="true" tabindex="-1"></a>  <span class="va">$output</span> <span class="kw">)</span> <span class="bu">echo</span> <span class="st">&quot;Input should be different from output&quot;</span> <span class="cf">;;</span></span>
<span id="cb1-4"><a href="SC2254.html#cb1-4" aria-hidden="true" tabindex="-1"></a><span class="cf">esac</span></span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2254.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="cf">case</span> <span class="va">$input</span> <span class="kw">in</span></span>
<span id="cb2-2"><a href="SC2254.html#cb2-2" aria-hidden="true" tabindex="-1"></a>  <span class="ss">-</span>         <span class="kw">)</span> <span class="bu">echo</span> <span class="st">&quot;Reading from stdin...&quot;</span> <span class="cf">;;</span></span>
<span id="cb2-3"><a href="SC2254.html#cb2-3" aria-hidden="true" tabindex="-1"></a>  <span class="st">&quot;</span><span class="va">$output</span><span class="st">&quot;</span> <span class="kw">)</span> <span class="bu">echo</span> <span class="st">&quot;Input should be different from output&quot;</span> <span class="cf">;;</span></span>
<span id="cb2-4"><a href="SC2254.html#cb2-4" aria-hidden="true" tabindex="-1"></a><span class="cf">esac</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>When unquoted variables and command expansions are used in case
branch patterns, they will be interpreted as globs.</p>
<p>This can lead to some surprising behavior, such as
<code>case $x in $x) trigger;; esac</code> not triggering in some cases,
such as when <code>x='Pride and Prejudice [1813].epub'</code>.</p>
<p>To match the literal content of the variable or expansion, make sure
to double quote the expansion.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>If you intended to match a dynamically generated pattern, you can
ignore this suggestion with a directive.</p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li><a href="SC2053.html">SC2053</a>, where the same effect can be seen with
<code>[[ $x = $x ]]</code>.</li>
<li>Help by adding links to BashFAQ, StackOverflow, man pages, POSIX,
etc!</li>
</ul>
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